【发布时间】：2016-01-03 22:40:05
【问题描述】：
我正在尝试创建一个正交矩阵，以及一个适当的模型和视图矩阵来查看一个简单的三角形，只是为了测试矩阵。我一直得到一个空白屏幕，我不知道发生了什么。我使用的是 LWJGL，而对于顶点和矩阵，我使用的是一个名为 JOML 的库。
主类（唯一的类）：
import static org.lwjgl.glfw.GLFW.*;
import static org.lwjgl.opengl.GL11.*;
import static org.lwjgl.opengl.GL20.*;
import static org.lwjgl.system.MemoryUtil.NULL;
import java.io.*;
import java.nio.*;
import org.joml.*;
import org.lwjgl.*;
import org.lwjgl.glfw.*;
import org.lwjgl.opengl.*;
public class Main {
private GLFWErrorCallback errorCallback;
private GLFWKeyCallback keyCallback;
private long window;
int WIDTH = 800, HEIGHT = 600;
public void run() {
System.out.println("Hello LWJGL " + Version.getVersion() + "!");
try {
init();
loop();
glfwDestroyWindow(window);
keyCallback.release();
} finally {
glfwTerminate();
errorCallback.release();
}
}
private void init() {
//initializes window
glfwSetErrorCallback(errorCallback = GLFWErrorCallback.createPrint(System.err));
if (glfwInit() != GLFW_TRUE)
throw new IllegalStateException("Unable to initialize GLFW");
glfwDefaultWindowHints();
glfwWindowHint(GLFW_VISIBLE, GLFW_FALSE);
glfwWindowHint(GLFW_RESIZABLE, GLFW_TRUE);
window = glfwCreateWindow(WIDTH, HEIGHT, "Hello World!", NULL, NULL);
if (window == NULL)
throw new RuntimeException("Failed to create the GLFW window");
glfwSetKeyCallback(window, keyCallback = new GLFWKeyCallback() {
@Override
public void invoke(long window, int key, int scancode, int action, int mods) {
if (key == GLFW_KEY_ESCAPE && action == GLFW_RELEASE)
glfwSetWindowShouldClose(window, GLFW_TRUE);
}
});
GLFWVidMode vidmode = glfwGetVideoMode(glfwGetPrimaryMonitor());
glfwSetWindowPos(window, (vidmode.width() - WIDTH) / 2, (vidmode.height() - HEIGHT) / 2);
glfwMakeContextCurrent(window);
glfwSwapInterval(1);
glfwShowWindow(window);
}
private void loop() {
//Loads and initializes shaders
GL.createCapabilities();
//glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
int shaderProgram = glCreateProgram();
int vertexShader = glCreateShader(GL_VERTEX_SHADER);
int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
StringBuilder vertexShaderSource = new StringBuilder();
StringBuilder fragmentShaderSource = new StringBuilder();
BufferedReader reader = null;
try {
reader = new BufferedReader(new FileReader("src/test/com/shader.vert"));
String line;
while((line = reader.readLine()) != null) {
vertexShaderSource.append(line).append('\n');
}
reader.close();
} catch(IOException e) {
System.err.println("Vertex shader not loaded properly!");
e.printStackTrace();
}
BufferedReader reader2 = null;
try {
reader2 = new BufferedReader(new FileReader("src/test/com/shader.frag"));
String line;
while((line = reader2.readLine()) != null) {
fragmentShaderSource.append(line).append('\n');
}
reader2.close();
} catch(IOException e) {
System.err.println("Fragment shader not loaded properly!");
e.printStackTrace();
}
glShaderSource(vertexShader, vertexShaderSource);
glCompileShader(vertexShader);
if(glGetShaderi(vertexShader, GL_COMPILE_STATUS) == GL_FALSE) {
System.err.println("Vertex shader not compiled correctly!");
}
glShaderSource(fragmentShader, fragmentShaderSource);
glCompileShader(fragmentShader);
if(glGetShaderi(fragmentShader, GL_COMPILE_STATUS) == GL_FALSE) {
System.err.println("Fragment Shader not compiled correctly!");
}
glAttachShader(shaderProgram, vertexShader);
glAttachShader(shaderProgram, fragmentShader);
glLinkProgram(shaderProgram);
glValidateProgram(shaderProgram);
//Matrices setup
FloatBuffer projectionFloat = BufferUtils.createFloatBuffer(16);
getProjectionMatrix(0, 800, 0, 600, -1, 1).get(projectionFloat);
glUniformMatrix4fv(glGetUniformLocation(shaderProgram, "projection"), false, projectionFloat);
FloatBuffer viewFloat = BufferUtils.createFloatBuffer(16);
getViewMatrix(new Vector3f(0, 0, 1), new Vector3f(0, 0, 0), new Vector3f(0, 1, 0)).get(viewFloat);
glUniformMatrix4fv(glGetUniformLocation(shaderProgram, "model"), false, viewFloat);
FloatBuffer modelFloat = BufferUtils.createFloatBuffer(16);
getModelMatrix().get(modelFloat);
glUniformMatrix4fv(glGetUniformLocation(shaderProgram, "model"), false, modelFloat);
//Main loop
while (glfwWindowShouldClose(window) == GLFW_FALSE) {
glClear(GL_COLOR_BUFFER_BIT);
glUseProgram(shaderProgram);
glBegin(GL_TRIANGLES);
{
glVertex3f(100, 100, 50);
glVertex3f(100, 400, 50);
glVertex3f(400, 400, 50);
}
glEnd();
glUseProgram(0);
glfwSwapBuffers(window);
glfwPollEvents();
}
}
public Matrix4f getModelMatrix() {
return new Matrix4f(
1, 0, 0, 0,
0, 1, 0, 0,
0, 0, 1, 0,
0, 0, 0, 1
);
}
public Matrix4f getProjectionMatrix(float bottom, float top, float left, float right, float near, float far) {
return new Matrix4f(
(2 / (right - left)), 0, 0, -((right + left) / (right - left)),
0, (2/(top - bottom)), 0, -((top + bottom) / (top - bottom)),
0, 0, (2 / (far - near)), -((far + near) / (far - near)),
0, 0, 0, 1
);
}
public Matrix4f getViewMatrix(Vector3f eye, Vector3f target, Vector3f up) {
Vector3f zAxis = eye.sub(target);
Vector3f xAxis = up.cross(zAxis);
Vector3f yAxis = zAxis.cross(xAxis);
return new Matrix4f(
xAxis.x, yAxis.x, zAxis.x, 0,
xAxis.y, yAxis.y, zAxis.y, 0,
xAxis.z, yAxis.z, zAxis.z, 0,
-xAxis.dot(eye), -yAxis.dot(eye), -zAxis.dot(eye), 1
);
}
public static void main(String[] args) {
new Main().run();
}
}
顶点着色器：
varying vec3 color;
in vec4 position;
uniform mat4 projection;
uniform mat4 view;
uniform mat4 model;
void main() {
color = gl_Color.rgb;
gl_Position = projection * view * model * position;
}
片段着色器：
varying vec3 color;
void main() {
gl_FragColor = vec4(color, 1);
}
【问题讨论】：
-
glUniform*()适用于当前程序。您需要在这些电话之前致电glUseProgram()。 -
我不是 opengl 专家，但我从未见过有人将旧的 opengl 函数（如（glBegin、glVertex、glEnd 等）与现代 opengl（如着色器）混合在一起）。我认为要解决您需要使用顶点缓冲区对象和 glDrawArrays 来实际使用着色器进行渲染的问题。
-
@jas 你可以结合 GLSL 和旧的 GL
glBegin()/glEnd()但在这种情况下你不能使用core配置文件，因为没有布局等...compatibility个人资料是你的朋友